Modexia-mcp Server

The financial infrastructure for autonomous AI. Equips Claude and other agents with secure, programmable USDC smart accounts (ERC-4337). Tools exposed: get_balance, transfer_usdc, get_history. Features: Abstracted gas fees (Paymasters), native USDC settlement on Base, and strict developer-defined spending limits (Policy-as-Code) to eliminate LLM hallucination liability.

Documentation


name: modexia-mcp version: 0.4.1 description: The official Model Context Protocol (MCP) server for autonomous AI Agents to interact with Modexia's crypto infrastructure. author: Modexia homepage: https://github.com/Modexia/ModexiaAgentpay tags:

  • mcp
  • web3
  • payments avatar: https://raw.githubusercontent.com/Modexia/ModexiaAgentpay/main/apps/mcp-server/assets/modexialogo.png config: type: stdio command: uvx args:
    • modexia-mcp skills:
  • nanopay
  • nanopay_activate
  • nanopay_deposit
  • nanopay_withdraw
  • nanopay_balance
  • submit_intent
  • get_intent
  • list_intents
  • open_channel
  • consume_channel
  • settle_channel
  • get_channel
  • list_channels
  • get_balance
  • get_history
  • transfer
  • cross_chain_transfer
  • smart_fetch prompts:
  • nanopay_usage_instruction
  • create_intent_payment_instruction
  • setup_microtransactions_instruction
  • create_payment_instruction resources:
  • modexia://docs/llms_context

Modexia Logo

Modexia AgentPay MCP Server

The official Model Context Protocol (MCP) server for autonomous AI Agents to interact with Modexia's crypto infrastructure.

PyPI version License: MIT

[![MCP Badge](https://lobehub.com/badge/mcp-full/modexia-modexia-mcp?theme=light)](https://lobehub.com/mcp/modexia-modexia-mcp)

Welcome to the Modexia AgentPay MCP Server (modexia-mcp). This server bridges the gap between Large Language Models and the real-world digital economy.

By integrating this standard Model Context Protocol (MCP) server into your AI stack (Claude Desktop, LobeChat, Dify, or custom multi-agent swarms), you instantly equip your AI Agents with a programmatic Smart Contract Wallet.

Instead of your agents hitting 402 Payment Required errors and failing, they can now autonomously negotiate paywalls, purchase premium data, execute zero-gas microtransactions via Circle Gateway, and trade compute resources with other agents in high-frequency vault channels.

Modexia gives your AI a bank account, and MCP gives it the tools to use it.


What's New in v0.4.1

Circle Gateway Nanopayments (x402) This release brings full agentic support for gas-free, sub-cent microtransactions directly to the MCP level.

  • nanopay — Fetch an x402-protected URL and automatically negotiate the payment using EIP-3009 offline signatures. Includes inline auto-refill logic.
  • nanopay_activate — One-time activation for the agent.
  • nanopay_deposit / nanopay_withdraw — Manage gateway funds directly from the main wallet.
  • nanopay_balance — Track the True Available Balance (Gateway deposits minus pending/unsettled signatures).
  • Structured Error Handling — The MCP tools now pass back structured ModexiaPaymentError codes (e.g., INSUFFICIENT_MAIN_BALANCE) so the LLM can reason about failures and take corrective action.

Previous: What's New in v0.3.0 (Intent-to-Pay)

Intent-Based Payments (v2) Execute standard USDC payments through a strict compliance pipeline with rich feedback.

  • submit_intent — Create a signed intent, validate against policies, and execute on-chain.
  • get_intent / list_intents — Audit trail and tracking.

Features

  • Circle Gateway Integration: Direct programmatic access to Circle's USDC nanopayment infrastructure.
  • Gas-Free Microtransactions: Send payments as low as $0.000001 with zero blockchain fees.
  • EIP-3009 Offline Signatures: Secure, off-chain payment authorizations that prevent double-spending.
  • Intent-Based Routing: Strict policy enforcement, daily spend limits, and cryptographic audit trails.
  • Automated Paywall Negotiation: Automatically detect 402 Payment Required headers and fulfill them inline.
  • Smart Auto-Refill: Seamlessly top-up gateway balances from the main wallet when funds run low.

Exposed MCP Components

Tools

Tool NameDescription
nanopayAuto-negotiate and pay for 402 Payment Required URLs using EIP-3009 offline signatures.
nanopay_activateOne-time activation command to enable Circle Gateway nanopayments for the agent.
nanopay_depositDeposit funds from the main agent wallet to the nanopayment Gateway.
nanopay_withdrawWithdraw unused funds from the Gateway back to the main wallet.
nanopay_balanceCheck the True Available Balance (Gateway deposits minus pending signatures).
submit_intentExecute a standard USDC payment with compliance and policy enforcement.
get_intentRetrieve the status and compliance metadata of a previously submitted payment intent.
list_intentsFetch recent payment intents for audit trail review.
open_channelLock funds into a smart contract for high-frequency micro-transactions.
consume_channelExecute instant, gas-free micro-payments inside an open channel.
settle_channelClose the vault and distribute funds on-chain.
get_channelCheck the current capacity and state of a specific payment channel.
list_channelsList all payment channels associated with the agent's wallet.
get_balanceRetrieve the current USDC balance of the agent's primary Smart Contract Wallet.
get_historyFetch the recent transaction history for the agent.
transferExecute a standard synchronous USDC transfer (v1).
cross_chain_transferExecute a cross-chain CCTP payment via Squid Router (e.g., Ethereum -> Akash).
smart_fetchLegacy HTTP auto-negotiation for HTTP-based Paywalls.

Prompts

Prompt NameDescription
nanopay_usage_instructionBest practices for funding the gateway and executing nanopay operations.
create_intent_payment_instructionRules for structuring compliant payments, adding memos, and handling policy rejections.
setup_microtransactions_instructionStep-by-step guide on opening, consuming, and settling vault channels.
create_payment_instructionStandard rules for legacy idempotency-based transfers.

Resources

Resource URIDescription
modexia://docs/llms_contextThe complete Modexia Developer Protocol Guide with overarching economic rules for swarms.

Configuration & Setup

This server requires a Modexia API Key to function. You can obtain one by creating a developer account at modexia.software.

VariableDescription
MODEXIA_API_KEYRequired. Your Modexia developer key (e.g. mx_test_...)
MODEXIA_BASE_URLOptional. Overrides the API endpoint. Defaults to the Sandbox Environment.

Using uvx (Recommended)

You can run this server directly in any MCP client that supports standard executable commands:

uvx modexia-mcp

Claude Desktop

To use Modexia with Claude Desktop, add the following to your claude_desktop_config.json:

{
  "mcpServers": {
    "modexia": {
      "command": "uvx",
      "args": ["modexia-mcp"],
      "env": {
        "MODEXIA_API_KEY": "mx_test_YourApiKeyHere"
      }
    }
  }
}

Contributing to Open Source

We actively welcome community contributions to make this MCP server even better. Because it acts as the primary interface for autonomous AI agents, we heavily prioritize stability and strict prompt engineering.

  1. Clone the Repo: git clone https://github.com/Modexia/modexia-mcp.git
  2. Install Dependencies: pip install -e .
  3. Run Locally: You can run the server in stdio mode for local testing via python -m modexia_mcp
  4. Submit PRs: Open a Pull Request targeting the main branch.

Security Model

The Modexia MCP Server never exposes your private keys to the LLM context. The AI only has permission to trigger explicitly configured MCP tools. Policy limits (e.g., maximum daily spend, hourly caps) are enforced automatically on the Modexia backend. Even a hallucinating AI cannot drain your wallet above your predefined guards.

License & Support

modexia-mcp is an open-source tool governed by the MIT License.

Need help scaling your agent swarm or configuring your API keys? Access your developer dashboard and explore the docs at modexia.software.